In many surgical procedures, it is often necessary to ligate a plurality of vessels within the surgical site. The vessels may be severed downstream of the ligated portion. In some instances, the vessels may be ligated in spaced apart areas and the portion of the vessel between the ligations removed. The purpose of ligating vessels is to maintain the surgical site free from an excess of blood and reduce blood loss in the patient. Also, in certain surgical procedures where tumors and the like are to be removed, the tumor or organ may have to be separated from certain vessels. Before separating, the vessels are ligated. Once a blood vessel is completely shut off, hemostasis, that is, the natural closing of the end of the vessel so as to stop blood flow, will occur in several days depending on the vessel. The body, in the meantime, will continue to allow blood flow around the ligated area through appropriate capillaries and secondary vessels with the natural physiological function of the body enlarging these bypass vessels until adequate blood flow is obtained. Hence, when ligating the vessel, there should be positive stoppage of the blood flow in the main vessel. Failure to provide complete stoppage may cause blood loss in the patient and may also disrupt the natural hemostatis and concurrent manufacture of new passages for blood flow in the patient.
In the past, the closing of the vessel was usually accomplished using sutures; that is, filaments or threads which the doctor tied around the vessel to be closed. This is a time-consuming process and one wherein positive closure of the vessel is not always accomplished. In recent years, hemostatic clips have replaced ligatures in surgical procedures to close blood vessels and other fluid ducts. Very often, these hemostatic clips are narrow U or V shaped strips formed of tantalum or stainless steel which are capable of being deformed and possess sufficient strength to retain the deformation when clamped about a blood vessel. Recently, clips have been produced from various types of bio-compatible polymeric materials which are absorbable or non-absorbable in body tissue. Representative hemostatic clips made from polymeric materials are more fully described in co-pending commonly assigned U.S. patent application Ser. Nos. 276,131 filed June 22, 1981, 282,165 filed July 31, 1981, and (ETH 532).
The hemostatic clips should be constructed so that in use they positively lock the vessel closed. The clip should not be able to be moved or disrupted by the surgeon working in the operative cavity either with an instrument or by a sponge or the like. Also, the clip should be constructed so that it may be made of virtually any type of polymeric material whether it be absorbable or non-absorbable, and whether the polymer be resilient or non-resilient, deformable or non-deformable, etc. The clip should be simple to manipulate and handle by both the nurse and the surgeon and preferably should be simple and inexpensive to manufacture.
What we have discovered is an improved ligating clip structure which allows the clip to be made from substantially non-resilient and non-deformable material as well as from resilient and deformable materials. Our new configuration produces a clip which positively closes a blood vessel for a sufficient period of time to provide hemostasis and make a suitable hemostatic clip. Our clip configuration in the closed position is such that it is relatively inmovable if inadvertently hit by an instrument or sponge or the like. Our new clip is easy to manufacture by simple molding techniques well known in the art.